Pharmacology Tutoring Respiratory Drugs

How does the upper respiratory tract expel foreign objects?

-sneezing

-excessive mucus production

What needs to be stimulated to elicit a coughing response?

-larynx

-trachea

-bronchi

-larger bronchioles

List the respiratory protective mechanisms

-laryngospasm

-sheet of sticky mucus on trachea and bronchioles, bronchospasm, and macrophages to engulf particles in the alveoli

What are the 3 things that can cause bronchoconstriction?

-parasympathetic stimulation

-histamine release

-irritant receptors

What causes bronchodilation?

sympathetic nervous system (remember beta 2 receptors from cardio?)

When you block B2 receptors, what occurs?

allow parasympathetic system to dominate so it causes bronchoconstriction

When you block cholinergic receptors, what occurs?

allows sympathetic system to dominate and causes bronchodilation

What are the inflammatory mediators that also cause bronchoconstriction?

prostaglandins, leukotrienes, serotonin and histamine

What does serotinin play a role in?

cat asthma (doesn't really have an affect on dog bronchoconstriction)

How dose the mucociliary apparatus work?

mucus gland excretes sticky mucus on the surface of epithelial cells, particles are inhaled and land on the mucus cilia move the mucus to the larynx where it is expelled or swallowed

mucus sheet + ciliated epithelium = ?

mucociliary apparatus or mucociliary elevator

What are the 2 actions the mucocilary system are responsible for?

secretory and mechanical

What action do beta receptor agonists increase?

ciliary action (secretory and mechanical)

What is induced by muscarinic stimulation?

secretory action (basically saying there is increased mucus production)

Name the defense mechanism that is comprised of monocytes, macrophages and dendritic cells.

Respiratory mononuclear phagocyte system

What is the defense mechanism that protects against infection and releases mediators of inflammation?

Respiratory mononuclear phagocyte system

What happens when the respiratory mononuclear phagocyte system releases mediators of inflammation?

decreases airway diameter

What are the 4 main strategies for treatments of respiratory issues?

-modify airway resistance

-increase respiratory secretions

-suppress the cough reflex

-stimulate respiration

What is the goal of modifying airway resistance?

making it easier for air to move in and out especially in depper parts of respiratory tree, to eliminate obstruction due to secretions or edema

What is the goal of increasing respiratory secretions?

making mucus thinner and easier to clear out

When should you NOT suppress the cough reflex?

When the patient has a productive cough

What are the most effective bronchodilator drugs?

Beta-adrenergic agonists and anticholinergic agents

What are the bronchodilator drugs that act on smooth muscles and decrease mucosal edema?

beta adrenergic agonists

What are the bronchodilator drugs that have anti-inflammatory actions and decrease release of inflammatory mediators?

beta adrenergic agonists

What receptors do bronchodilators work on? What do they do?

-beta 2 receptors

-bronchodilation, increase watery secretion and rate of ciliary movement

What decongestant increase vascular smooth muscle constriction and decrease blood floow in bronchial mucosa?

alpha-adrenergic agonists

With what diseases would bronchodilators and decongestants be used for?

COPD, asthma, decompensated congestive heart failure, intrathoracic tracheal collapse, bronchospasm, sinusitis, sinusitis, rhinitis, rhinorrhea

What drug is a mixed agonist and prototype of adrenaline?

epinephrine

What receptor is only in airways?

Beta 2 receptors

What do bronchodilators act on within the B1 receptors?

inotropic and chronotropic effect of relaxation of GI

What receptors are epinephrine an agonist for?

-alpha 1

-beta 1

-beta 2

What effects does epinephrine have?

bronchodilation, inotropic and chronotropic effect, vasoconstriction

When would you use epinephrine?

anaphylaxis, acute episodes of bronchospasm, mucous membrane decongestion (topical nasal spray)

What mixed agonist is best for anaphylaxis?

epinephrine

What toxicity can you see with epinephrine?

tremors, tachyarrhythmia, hypertension

When should you NOT use epinephrine?

in animals with a known heart conditon

What are 5 common beta agonist drugs?

-isoproterenol

-terbutaline

-albuterol

-clenbuterol

-salmeterol

What receptors does isopreteronol hit?

B1 and B2 adrenergic

What is isoproterenol?

bronchodilator

What is the duration of isoproterenol?

short, less than 1 hour

What do we mainly use isoproternol for?

VIA inhalation to treat bronchospasms in horses and emergencies, not for long term use

How may isoproternol be given?

Slow IV and mush dilute in saline

When should you discontinue isoproterenol?

when the patients heart rate doubles

What receptor does terbutaline hit?

B2 selective

What drug is terbutaline similar to? what are the differences?

similar to isoproterenol but longer acting and more selective

What is the duration of terbutaline?

6-8 hours

How is terbutaline given?

Orally, usually BID

When is terbutaline contraindicated?

in cats with cardiomyopathy and glaucoma

What is terbutaline used for?

cats not having severe bronchoconstriction episodes despite corticosteroids

What is the duration of albuterol?

SHORT actung use only

How can you give albuterol and what is the reason for giving this drug?

MDI or nebulization for acute bronchoconstriction

What is know as the rescue inhaler?

albuterol

What three species is albuterol the rescue inhaler for?

Cats, Horses, Cattle

Long-term use of this beta agonist will result in B2-receptor down-regulation (making it less effective)

albuterol

For what species and for what reason do we use clenbuterol?

equine asthma only

Clenbuterol is short term unless concurrent with what?

anti-inflammatories

What can clenbuterol inhibit in horses and cattle?

uterine contractions

What is salmeterol?

long acting albuterol analog

When is salmeterol commonly used?

in horses and cats to improve airway conduction in bronchial asthma and bronchospasm due to bronchitis or emphysema, as well as horses with COPD and pneumonia

Where might we see albuterol toxicosis?

result of chewing on albuterol-containing inhalers used for humans

Which of the beta-agonist drugs is lipophilic?

salmeterol

What does MDI stand for?

metered dose inhaler

What is a MDI?

each depression of plunger on canister in the inhaler "doses" out a measured amount of drug

What does the spacer allow for in a MDI?

the drug mist to mix with room air and dilute out some of the taste on the concentrated drug

What is a nebulizer?

creates a mist that is inhaled

What is the problem with nebulizers?

droplets strike the sirway walls and adhere to it- causes difficulty getting drug deep into respiratory tree

Nebulizers can be used in horses with what problem?

recurrent airway obstruction (RAO)

What is phenylephrine?

alpha 1-agonist decongestants

Oral formulation of phenylephrine has what?

low bioavailability in our species so often combined with other ingredients toxic to our patients

What is the IV formulation of phenylephrine used for?

increase blood pressure via peripheral vasoconstriction

Why do you want to avoid pregnant animals when using phenylephrine?

uterine vasoconstriction

What does the topical formulation of phenylephrine cause?

topical vasoconstriction

What is a oral xanthine bronchodilator?

theoplylline

What effects does theophylline give?

-bronchodilator

-increases mucociliary clearance

-anti-inflammatory

-increases the strength of respiratory muscles

When is theophylline used?

-chronic asthma, myocardial failure, pulmonary edema

in cats

-cats with asthma used as a sustained release oral theophylline because of short half life

What toxicity effects might we see with theophylline?

sympathetic activity, agitation, tremors

What xanthine bronchodilator is used IV with O2 therapy in foals with respiratory distress syndrome?

aminophylline

Anticholinergics compete with acethycholine at which receptors?

muscarinic

What do anticholinergics antagonize?

vagally mediated bronchoconstriction

What does anticholinergics reduce sensitivity to?

irritant receptors

What are the anticholinergic side effects?

can't see, can't pee, can't spit, can't shit

What anticholinergic can be given via aerosol or IV?

atropine

What anticholinergic commonly increase heart rate, facilitates bronchodilation in dyspneic animals and is the drug of choice for respiratory distress caused by anti-choliesterasrs?

atropine

What systemic side effects come along with atropine?

reduces mucociliary clearance,

induces tachycardia

urine retention

decreases gastric motility

Should you use atropine chronically?

NO

How is ipratropium bromide different from atropine?

less systemic effects: not absorbed as well as atropine following aerolization, can be given chronically

What is an anticholinergic bronchodilator in small animals?

Glycopyrrolate

Which anticholinergic has a longer duration of action compared to atropine and has fewer side effects?

Gycopyrrolate

What anticholinergic is twice as potent as atropine when used as an aerosol?

glycopyrrolate

What impulses travel down to the diaphragm and respiratory muscles to produce a forceful expiration?

motor impulses

Stimulus in the larynx and upper trachea will produce what kind of cough?

sudden, retching, gagging

Lower trachea, bronchi, larger bronchioles produces what kind of cough?

controlled, coordinated deep cough

Stimulus from where will not produce a cough?

terminal bronchioles or alveoli

What are the two classifications of coughs?

productive and non-productive

How can a productive cough be characterized?

mucus being coughed up and expelled

How can a non-productive cough be characterized?

sharp cough but no mucus brought up

When will we see a non-productive cough?

Early stages of respiratory disease,

inspissated mucus (dried out mucus), dehydrated animals

When should you suppress a cough?

mechanical irritation on bronchi, infectious diseases if non productive, exhaustion associated with coughing, collapsing trachea

What drug classes can we use to suppress a cough?

Central acting cough suppressants: for non-productive cough, bronchodilators, mucokinetic drugs and expectorants (removal of the irritant)

What do centrally acting antitussives inhibit?

medullary cough center by reducing its sensitivity to stimuli